The invention relates to a drive unit for a motor vehicle with a hybrid drive and a drive train in a longitudinal arrangement, which drive train also comprises an internal combustion engine, a longitudinal shaft for driving a first axle, and a gear mechanism, and which drive unit is arranged between the internal combustion engine and the first axle and comprises a housing part, a through-drive shaft, an electrical machine surrounding the through-drive shaft and a first clutch upstream of and a second clutch downstream of the electrical machine. With the longitudinal arrangement, the permanently driven, in this case the first, axle is generally the rear axle.
Such a drive train is known from DE 29 43 554 C2, but is only illustrated schematically. The rotation speed ratios and structural features are now shown. In any case the electrical machine is used both as a drive or an additional drive and as a starter and generator. A few more details, if only for a drive train having a transverse design, are given in EP 775 607 B1. Therein, the electrical machine has a relatively high rotation speed and is connected to the axle drive via a planetary gear mechanism, as is the internal combustion engine. The planetary gear mechanism is a superposition gear mechanism, in which the two drive torques are added to one another. This has the disadvantage that if only one of the two drives is working, the other needs to be blocked in order to provide a supporting torque. Furthermore, a purely electromotive drive for the second axle is added there. In order to accommodate such an additional drive on a rear axle, there is too little space there without altering the design. If, in the case of a drive train with a longitudinal design, the second driven axle is intended to be the front axle, it is not possible to solve this problem of space and it is also necessary to extensively alter the entire vehicle.